GA/T 1481.2-2018BeiDou/global navigation satellite system for police application--Part 2: Technical requirements for terminal positioning (English PDF)

2.1 Definition of terms

The following terms and definitions apply to this document.

2.1.1

Beidou/Global Satellite Navigation System Police Terminal policeterminalwithBeiDou/globalnavigationsatelitesystem Equipment equipped with BDS/GNSS navigation and positioning functions for public security organs on duty, law enforcement, and use.

2.1.2

Positioning

A process or technique for determining the location of a user using measurement information.

2.1.3

Positioning accuracy A statistical value of the difference between the observed position value and the true position value.

2.1.4

Speed accuracy velocityaccuracy the statistical value of the difference between the observed velocity and the true velocity.

2.1.5

Recapture time reacquisitiontime After the received navigation signal is lost for a short time, the user equipment recovers from the signal to the time required to recapture the navigation signal.

2.1.6

Capture sensitivity acquisitionsensitivity the minimum signal level required for the user equipment to capture the navigation signal and properly locate it under cold-start conditions.

2.1.7

Recapture sensitivity reacquisitionsensitivity After the received navigation signal is lost for a short time, the user equipment recaptures the navigation signal and normally locates the minimum signal level required.

2.1.8

Tracking sensitivity After normal positioning, the user equipment can continue to maintain the minimum signal level required for tracking and positioning of the navigation signals.

2.1.9

Hot start first positioning time hotstarttimetofirstfix the time required for the user equipment to go from power-on to normal positioning in a state where the ephemeris, almanac, summary time, and approximate location are known.